Author: Jane Gilman
Publisher: American Mathematical Soc.
ISBN: 0821803611
Category : Gardening
Languages : en
Pages : 221
Book Description
The discreteness problem is the problem of determining whether or not a two-generator subgroup of $PSL(2, R)$ is discrete. Historically, papers on this old and subtle problem have been known for their errors and omissions. This book presents the first complete geometric solution to the discreteness problem by building upon cases previously presented by Gilman and Maskit and by developing a theory of triangle group shinglings/tilings of the hyperbolic plane and a theory explaining why the solution must take the form of an algorithm. This work is a thoroughly readable exposition that captures the beauty of the interplay between the algebra and the geometry of the solution.
Two-Generator Discrete Subgoups of $PSL(2, R)$
Author: Jane Gilman
Publisher: American Mathematical Soc.
ISBN: 0821803611
Category : Gardening
Languages : en
Pages : 221
Book Description
The discreteness problem is the problem of determining whether or not a two-generator subgroup of $PSL(2, R)$ is discrete. Historically, papers on this old and subtle problem have been known for their errors and omissions. This book presents the first complete geometric solution to the discreteness problem by building upon cases previously presented by Gilman and Maskit and by developing a theory of triangle group shinglings/tilings of the hyperbolic plane and a theory explaining why the solution must take the form of an algorithm. This work is a thoroughly readable exposition that captures the beauty of the interplay between the algebra and the geometry of the solution.
Publisher: American Mathematical Soc.
ISBN: 0821803611
Category : Gardening
Languages : en
Pages : 221
Book Description
The discreteness problem is the problem of determining whether or not a two-generator subgroup of $PSL(2, R)$ is discrete. Historically, papers on this old and subtle problem have been known for their errors and omissions. This book presents the first complete geometric solution to the discreteness problem by building upon cases previously presented by Gilman and Maskit and by developing a theory of triangle group shinglings/tilings of the hyperbolic plane and a theory explaining why the solution must take the form of an algorithm. This work is a thoroughly readable exposition that captures the beauty of the interplay between the algebra and the geometry of the solution.
Computational Aspects of Discrete Subgroups of Lie Groups
Author: Alla Detinko
Publisher: American Mathematical Society
ISBN: 1470468042
Category : Mathematics
Languages : en
Pages : 164
Book Description
This volume contains the proceedings of the virtual workshop on Computational Aspects of Discrete Subgroups of Lie Groups, held from June 14 to June 18, 2021, and hosted by the Institute for Computational and Experimental Research in Mathematics (ICERM), Providence, Rhode Island. The major theme deals with a novel domain of computational algebra: the design, implementation, and application of algorithms based on matrix representation of groups and their geometric properties. It is centered on computing with discrete subgroups of Lie groups, which impacts many different areas of mathematics such as algebra, geometry, topology, and number theory. The workshop aimed to synergize independent strands in the area of computing with discrete subgroups of Lie groups, to facilitate solution of theoretical problems by means of recent advances in computational algebra.
Publisher: American Mathematical Society
ISBN: 1470468042
Category : Mathematics
Languages : en
Pages : 164
Book Description
This volume contains the proceedings of the virtual workshop on Computational Aspects of Discrete Subgroups of Lie Groups, held from June 14 to June 18, 2021, and hosted by the Institute for Computational and Experimental Research in Mathematics (ICERM), Providence, Rhode Island. The major theme deals with a novel domain of computational algebra: the design, implementation, and application of algorithms based on matrix representation of groups and their geometric properties. It is centered on computing with discrete subgroups of Lie groups, which impacts many different areas of mathematics such as algebra, geometry, topology, and number theory. The workshop aimed to synergize independent strands in the area of computing with discrete subgroups of Lie groups, to facilitate solution of theoretical problems by means of recent advances in computational algebra.
Algebraic Generalizations of Discrete Groups
Author: Benjamin Fine
Publisher: CRC Press
ISBN: 9780824703196
Category : Mathematics
Languages : en
Pages : 338
Book Description
A survey of one-relator products of cyclics or groups with a single defining relation, extending the algebraic study of Fuchsian groups to the more general context of one-relator products and related group theoretical considerations. It provides a self-contained account of certain natural generalizations of discrete groups.
Publisher: CRC Press
ISBN: 9780824703196
Category : Mathematics
Languages : en
Pages : 338
Book Description
A survey of one-relator products of cyclics or groups with a single defining relation, extending the algebraic study of Fuchsian groups to the more general context of one-relator products and related group theoretical considerations. It provides a self-contained account of certain natural generalizations of discrete groups.
The Structure of $k$-$CS$- Transitive Cycle-Free Partial Orders
Author: Richard Warren
Publisher: American Mathematical Soc.
ISBN: 082180622X
Category : Mathematics
Languages : en
Pages : 183
Book Description
The class of cycle-free partial orders (CFPOs) is defined, and the CFPOs fulfilling a natural transitivity assumption, called k-connected set transitivity (k-CS-transitivity), are analysed in some detail. Classification in many of the interesting cases is given. This work generlizes Droste's classification of the countable k-transitive trees (k>1). In a CFPO, the structure can be branch downwards as well as upwards, and can do so repeatedely (though it neverr returns to the starting point by a cycle). Mostly it is assumed that k>2 and that all maximal chains are finite. The main classification splits into the sporadic and skeletal cases. The former is complete in all cardinalities. The latter is performed only in the countable case. The classification is considerably more complicated than for trees, and skeletal CFPOs exhibit rich, elaborate and rather surprising behaviour.
Publisher: American Mathematical Soc.
ISBN: 082180622X
Category : Mathematics
Languages : en
Pages : 183
Book Description
The class of cycle-free partial orders (CFPOs) is defined, and the CFPOs fulfilling a natural transitivity assumption, called k-connected set transitivity (k-CS-transitivity), are analysed in some detail. Classification in many of the interesting cases is given. This work generlizes Droste's classification of the countable k-transitive trees (k>1). In a CFPO, the structure can be branch downwards as well as upwards, and can do so repeatedely (though it neverr returns to the starting point by a cycle). Mostly it is assumed that k>2 and that all maximal chains are finite. The main classification splits into the sporadic and skeletal cases. The former is complete in all cardinalities. The latter is performed only in the countable case. The classification is considerably more complicated than for trees, and skeletal CFPOs exhibit rich, elaborate and rather surprising behaviour.
Some Connections between Isoperimetric and Sobolev-type Inequalities
Author: Serguei Germanovich Bobkov
Publisher: American Mathematical Soc.
ISBN: 0821806424
Category : Art
Languages : en
Pages : 127
Book Description
For Borel probability measures on metric spaces, this text studies the interplay between isoperimetric and Sobolev-type inequalities. In particular the question of finding optimal constants via isoperimetric quantities is explored. Also given are necessary and sufficient conditions for the equivalence between the extremality of some sets in the isoperimetric problem and the validity of some analytic inequalities. The book devotes much attention to: the probability distributions on the real line; the normalized Lebesgue measure on the Euclidean sheres; and the canonical Gaussian measure on the Euclidean space.
Publisher: American Mathematical Soc.
ISBN: 0821806424
Category : Art
Languages : en
Pages : 127
Book Description
For Borel probability measures on metric spaces, this text studies the interplay between isoperimetric and Sobolev-type inequalities. In particular the question of finding optimal constants via isoperimetric quantities is explored. Also given are necessary and sufficient conditions for the equivalence between the extremality of some sets in the isoperimetric problem and the validity of some analytic inequalities. The book devotes much attention to: the probability distributions on the real line; the normalized Lebesgue measure on the Euclidean sheres; and the canonical Gaussian measure on the Euclidean space.
Crossed Products with Continuous Trace
Author: Siegfried Echterhoff
Publisher: American Mathematical Soc.
ISBN: 0821805630
Category : Mathematics
Languages : en
Pages : 149
Book Description
This memoir presents an extensive study of strongly continuous actions of abelian locally compact groups on [italic capital]C*-algebras with continuous trace. Expositions of the Mackey-Green-Rieffel machine of induced representations and the theory of Morita equivalent [italic capital]C*-dynamical systems are included. There is also an elaboration of the representation theory of crossed products by actions of abelian groups on type I [italic capital]C*-algebras.
Publisher: American Mathematical Soc.
ISBN: 0821805630
Category : Mathematics
Languages : en
Pages : 149
Book Description
This memoir presents an extensive study of strongly continuous actions of abelian locally compact groups on [italic capital]C*-algebras with continuous trace. Expositions of the Mackey-Green-Rieffel machine of induced representations and the theory of Morita equivalent [italic capital]C*-dynamical systems are included. There is also an elaboration of the representation theory of crossed products by actions of abelian groups on type I [italic capital]C*-algebras.
Geometry of Loop Spaces and the Cobar Construction
Author: Hans J. Baues
Publisher: American Mathematical Soc.
ISBN: 0821822306
Category : Mathematics
Languages : en
Pages : 194
Book Description
The homology of iterated loop spaces [capital Greek]Omega [superscript]n [italic]X has always been a problem of major interest because it gives some insight into the homotopy of [italic]X, among other things. Therefore, if [italic]X is a CW-complex, one has been interested in small CW models for [capital Greek]Omega [superscript]n [italic]X in order to compute the cellular chain complex. The author proves a very general model theorem from which he can derive models, in addition to very technical proofs of the model theorem for several other models.
Publisher: American Mathematical Soc.
ISBN: 0821822306
Category : Mathematics
Languages : en
Pages : 194
Book Description
The homology of iterated loop spaces [capital Greek]Omega [superscript]n [italic]X has always been a problem of major interest because it gives some insight into the homotopy of [italic]X, among other things. Therefore, if [italic]X is a CW-complex, one has been interested in small CW models for [capital Greek]Omega [superscript]n [italic]X in order to compute the cellular chain complex. The author proves a very general model theorem from which he can derive models, in addition to very technical proofs of the model theorem for several other models.
Model Theory and Linear Extreme Points in the Numerical Radius Unit Ball
Author: Michael A. Dritschel
Publisher: American Mathematical Soc.
ISBN: 0821806513
Category : Mathematics
Languages : en
Pages : 77
Book Description
This memoir initiates a model theory-based study of the numerical radius norm. Guided by the abstract model theory of Jim Agler, the authors propose a decomposition for operators that is particularly useful in understanding their properties with respect to the numerical radius norm. Of the topics amenable to investigation with these tools, the following are presented: a complete description of the linear extreme points of the non-matrix (numerical radius) unit ball; several equivalent characterizations of matricial extremals in the unit ball, that is, those members which do not allow a nontrivial extension remaining in the unit ball; and applications to numerical ranges of matrices, including a complete parameterization of all matrices whose numerical ranges are closed disks.
Publisher: American Mathematical Soc.
ISBN: 0821806513
Category : Mathematics
Languages : en
Pages : 77
Book Description
This memoir initiates a model theory-based study of the numerical radius norm. Guided by the abstract model theory of Jim Agler, the authors propose a decomposition for operators that is particularly useful in understanding their properties with respect to the numerical radius norm. Of the topics amenable to investigation with these tools, the following are presented: a complete description of the linear extreme points of the non-matrix (numerical radius) unit ball; several equivalent characterizations of matricial extremals in the unit ball, that is, those members which do not allow a nontrivial extension remaining in the unit ball; and applications to numerical ranges of matrices, including a complete parameterization of all matrices whose numerical ranges are closed disks.
Wavelet Methods for Pointwise Regularity and Local Oscillations of Functions
Author: Stéphane Jaffard
Publisher: American Mathematical Soc.
ISBN: 0821804758
Category : Mathematics
Languages : en
Pages : 127
Book Description
We investigate several topics related to the local behavior of functions: pointwise Hölder regularity, local scaling invariance and very oscillatory "chirp-like" behaviors. Our main tool is to relate these notions to two-microlocal conditions which are defined either on the Littlewood-Paley decomposition or on the wavelet transform. We give characterizations and the main properties of these two-microlocal spaces and we give several applications, such as bounds on the dimension of the set of Hölder singularities of a function, Sobolev regularity of trace functions, and chirp expansions of specific functions.
Publisher: American Mathematical Soc.
ISBN: 0821804758
Category : Mathematics
Languages : en
Pages : 127
Book Description
We investigate several topics related to the local behavior of functions: pointwise Hölder regularity, local scaling invariance and very oscillatory "chirp-like" behaviors. Our main tool is to relate these notions to two-microlocal conditions which are defined either on the Littlewood-Paley decomposition or on the wavelet transform. We give characterizations and the main properties of these two-microlocal spaces and we give several applications, such as bounds on the dimension of the set of Hölder singularities of a function, Sobolev regularity of trace functions, and chirp expansions of specific functions.
Stratifying Endomorphism Algebras
Author: Edward Cline
Publisher: American Mathematical Soc.
ISBN: 082180488X
Category : Mathematics
Languages : en
Pages : 135
Book Description
This paper presents a systematic study of the relationships between the representation theories of [italic capital]R and [italic capital]A, especially those involving actual or potential quasi-hereditary structures on the latter algebra. Our original motivation comes from the theory of Schur algebras, work of Soergel on the Bernstein-Gelfand-Gelfand category [script capital]O, and resent results of Dlab-Heath-Marko realizing certain endomorphism algebras as quasi-hereditary algebras. We synthesize common features of all these examples, and go beyond them in a number of new directions.
Publisher: American Mathematical Soc.
ISBN: 082180488X
Category : Mathematics
Languages : en
Pages : 135
Book Description
This paper presents a systematic study of the relationships between the representation theories of [italic capital]R and [italic capital]A, especially those involving actual or potential quasi-hereditary structures on the latter algebra. Our original motivation comes from the theory of Schur algebras, work of Soergel on the Bernstein-Gelfand-Gelfand category [script capital]O, and resent results of Dlab-Heath-Marko realizing certain endomorphism algebras as quasi-hereditary algebras. We synthesize common features of all these examples, and go beyond them in a number of new directions.